The effect of wheel weight and rotational mass on power - Dyno testing three sets of 20 inch wheels

There is a reason car companies spend big money on exotic materials in order to reduce weight. Ford includes carbon fiber wheels on the Mustang GT350R because reducing rotational mass has quite an effect on performance.

The test below is an old one done by Davenport Motorsports but the physics remain true as ever.

The 12 pound difference between the lightest and heaviest set of wheels and tires is worth almost 11 wheel horsepower on the dyno despite the lighter wheel and tire combo also being wider.

Now, you are not making more power with lighter wheels and tires and the engine still has the same output. You are reducing losses though in that power getting to the ground. In other words, improving efficiency.

The question is if it's worth the price of admission for what you're getting. The 911 carbon wheels cost about $20K. So basically, you're spending about $20K to gain about 11whp. And God forbid you hit the curb or a pot hole. It reminds me of CCBs. At the track, people swap them out for steel units because of the cost of replacement.